The U.S. Court of Appeals for the Ninth Circuit in San Francisco, California.

President Donald Trump’s steady march to reshape the U.S. Court of Appeals for the Ninth Circuit hit a snag Thursday.

Just as Trump’s first Ninth Circuit nominee, Oregon federal prosecutor Ryan Bounds, was set to come up for a full Senate vote, Majority Leader Mitch McConnell announced the nomination had been withdrawn. The announcement came after his home-state Democratic senators opposed Bounds nomination, and as reports surfaced that Sen. Tim Scott, R-South Carolina, had concerns about the nominee’s college writings in which Bounds criticized “race-based” campus groups and efforts to promote multiculturalism.

Ninth Circuit watchers reached shortly after the news broke were surprised by the developments, but said that the whole episode sheds light on the challenges Trump faces in changing the makeup of the nation’s largest federal appellate court. Here are three takeaways from Bounds’ withdrawal.

1. It Only Takes One

The margin for error on nominations are razor thin in the current Senate. With Arizona Sen. John McCain out to get treatment on a serious form of brain cancer, Republicans hold a 50-49 majority in the Senate. Although Scott was among the 50 senators in the majority who voted along party lines to end debate on Bounds’ nomination Wednesday clearing the path for Thursday’s scheduled up-down vote, he ultimately told colleagues he wasn’t prepared to affirm the nomination.

“This is the sort of thing that happens when Republicans have essentially no room to lose votes,” said Ninth Circuit scholar Arthur Hellman, a professor emeritus at the University of Pittsburgh School of Law.

2. A Little Opposition Research Can Go a Long Way

To call the process that the ran up the Bounds nomination clunky would be generous.

When the nomination was initially announced last year, Oregon’s two Democratic U.S. senators—Ron Wyden and Jeff Merkley—refused to sign off on his nomination since he wasn’t vetted through their bipartisan selection committee. In February, after the senator’s committee convened, they included Bounds on a list of four candidates ranked the highest to the White House.

Bounds handed over undergraduate writings to the Judiciary Committee that he hadn’t handed over to the Oregon senators’ vettors—articles in which Bounds criticized “race-focused” campus groups and urged the school to adopt a “beyond a reasonable doubt” approach to campus sexual assault. Those writings were publicized by a liberal interest group opposed to his nomination.

Citing the lack of disclosure and the content of the writings, Wyden and Merkley urged the White House not to move forward with his nomination. The senators said that five of the seven members of their vetting committee said they would not have approved Bounds as a nominee had the writings been handed over.

“It was the dogged determination by the senators who were just embarrassed to have that nominee sitting for three decades in their state,” said Carl Tobias, a law professor at the University of Richmond School of Law.

Hellman added that ironically this was an instance where “hostile vetting” could have benefited the White House. “The more consultation you have with Democratic senators at an early stage the more likely they are” to turn something like this up, Hellman said. “The White House might have decided a long time ago the fight isn’t worth it. There are a lot of solid Republican lawyers in Oregon.”

3. This Isn’t the Way Things Have to Go

The Ninth Circuit currently has six vacancies and another set to open later this year when Idaho-based Judge N. Randy Smith plans to take senior status next month. The president still has a major opportunity to put his imprint on the 29-judge circuit. And there’s a pretty clear model for making the process work, even in states such as Oregon, Washington State and California that pit the administration against Democratic senators.

Even though he was nominated after Bounds, former Hawaii Attorney General Mark Bennett breezed through the Senate 72-27, in part because he had the backing of the state’s Democratic senators, Brian Schatz and Mazie K. Hirono, who seemed to have a better line of communication with the White House.

Court watchers say that getting the home state senators involvement and sign off, though not 100 percent necessary in the current setup, can certainly grease the Senate’s wheels. Not doing so can lead to 50-49 showdowns that result in the possibilities of a repeat of Thursday’s drama.

Said Tobias, “I don’t think 50-49 votes are very healthy for the Senate or for the courts.”

Read more:

Ryan Bounds, Trumps Ninth Circuit Nominee, Withdrawn From Senate Floor Vote 

Ninth Circuit Nominee Expresses Regret for Undergraduate Writings, but Insists He Didn’t Hide Them

3 Things to Watch For at Potentially Contentious 9th Circuit Confirmation Hearing 

Clarification: An earlier version of this story said that liberal interest groups “surfaced” Bounds’ undergraduate writings. Those writings were handed over to the Judiciary Committee and publicized by the interest group.